The U.S. government bought 112,000 acres of land in south eastern Colorado in 1968 for $17,500,000. The cost of using this land today exclusively for the reintroduction of the black-tailed prairie dog
a. Is zero, because they already own the land.
b. Is zero, because the land represents a sunk cost.
c. Is equal to the market value of the land.
d. Is equal to the total dollar value the land would yield if used for farming and ranching.